1// SPDX-License-Identifier: GPL-2.0-only
2/*
3 * intel-bts.c: Intel Processor Trace support
4 * Copyright (c) 2013-2015, Intel Corporation.
5 */
6
7#include <errno.h>
8#include <linux/kernel.h>
9#include <linux/types.h>
10#include <linux/bitops.h>
11#include <linux/log2.h>
12#include <linux/zalloc.h>
13
14#include "../../../util/cpumap.h"
15#include "../../../util/event.h"
16#include "../../../util/evsel.h"
17#include "../../../util/evlist.h"
18#include "../../../util/mmap.h"
19#include "../../../util/session.h"
20#include "../../../util/pmus.h"
21#include "../../../util/debug.h"
22#include "../../../util/record.h"
23#include "../../../util/tsc.h"
24#include "../../../util/auxtrace.h"
25#include "../../../util/intel-bts.h"
26#include <internal/lib.h> // page_size
27
28#define KiB(x) ((x) * 1024)
29#define MiB(x) ((x) * 1024 * 1024)
30#define KiB_MASK(x) (KiB(x) - 1)
31#define MiB_MASK(x) (MiB(x) - 1)
32
33struct intel_bts_snapshot_ref {
34	void	*ref_buf;
35	size_t	ref_offset;
36	bool	wrapped;
37};
38
39struct intel_bts_recording {
40	struct auxtrace_record		itr;
41	struct perf_pmu			*intel_bts_pmu;
42	struct evlist		*evlist;
43	bool				snapshot_mode;
44	size_t				snapshot_size;
45	int				snapshot_ref_cnt;
46	struct intel_bts_snapshot_ref	*snapshot_refs;
47};
48
49struct branch {
50	u64 from;
51	u64 to;
52	u64 misc;
53};
54
55static size_t
56intel_bts_info_priv_size(struct auxtrace_record *itr __maybe_unused,
57			 struct evlist *evlist __maybe_unused)
58{
59	return INTEL_BTS_AUXTRACE_PRIV_SIZE;
60}
61
62static int intel_bts_info_fill(struct auxtrace_record *itr,
63			       struct perf_session *session,
64			       struct perf_record_auxtrace_info *auxtrace_info,
65			       size_t priv_size)
66{
67	struct intel_bts_recording *btsr =
68			container_of(itr, struct intel_bts_recording, itr);
69	struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
70	struct perf_event_mmap_page *pc;
71	struct perf_tsc_conversion tc = { .time_mult = 0, };
72	bool cap_user_time_zero = false;
73	int err;
74
75	if (priv_size != INTEL_BTS_AUXTRACE_PRIV_SIZE)
76		return -EINVAL;
77
78	if (!session->evlist->core.nr_mmaps)
79		return -EINVAL;
80
81	pc = session->evlist->mmap[0].core.base;
82	if (pc) {
83		err = perf_read_tsc_conversion(pc, &tc);
84		if (err) {
85			if (err != -EOPNOTSUPP)
86				return err;
87		} else {
88			cap_user_time_zero = tc.time_mult != 0;
89		}
90		if (!cap_user_time_zero)
91			ui__warning("Intel BTS: TSC not available\n");
92	}
93
94	auxtrace_info->type = PERF_AUXTRACE_INTEL_BTS;
95	auxtrace_info->priv[INTEL_BTS_PMU_TYPE] = intel_bts_pmu->type;
96	auxtrace_info->priv[INTEL_BTS_TIME_SHIFT] = tc.time_shift;
97	auxtrace_info->priv[INTEL_BTS_TIME_MULT] = tc.time_mult;
98	auxtrace_info->priv[INTEL_BTS_TIME_ZERO] = tc.time_zero;
99	auxtrace_info->priv[INTEL_BTS_CAP_USER_TIME_ZERO] = cap_user_time_zero;
100	auxtrace_info->priv[INTEL_BTS_SNAPSHOT_MODE] = btsr->snapshot_mode;
101
102	return 0;
103}
104
105static int intel_bts_recording_options(struct auxtrace_record *itr,
106				       struct evlist *evlist,
107				       struct record_opts *opts)
108{
109	struct intel_bts_recording *btsr =
110			container_of(itr, struct intel_bts_recording, itr);
111	struct perf_pmu *intel_bts_pmu = btsr->intel_bts_pmu;
112	struct evsel *evsel, *intel_bts_evsel = NULL;
113	const struct perf_cpu_map *cpus = evlist->core.user_requested_cpus;
114	bool privileged = perf_event_paranoid_check(-1);
115
116	if (opts->auxtrace_sample_mode) {
117		pr_err("Intel BTS does not support AUX area sampling\n");
118		return -EINVAL;
119	}
120
121	btsr->evlist = evlist;
122	btsr->snapshot_mode = opts->auxtrace_snapshot_mode;
123
124	evlist__for_each_entry(evlist, evsel) {
125		if (evsel->core.attr.type == intel_bts_pmu->type) {
126			if (intel_bts_evsel) {
127				pr_err("There may be only one " INTEL_BTS_PMU_NAME " event\n");
128				return -EINVAL;
129			}
130			evsel->core.attr.freq = 0;
131			evsel->core.attr.sample_period = 1;
132			evsel->needs_auxtrace_mmap = true;
133			intel_bts_evsel = evsel;
134			opts->full_auxtrace = true;
135		}
136	}
137
138	if (opts->auxtrace_snapshot_mode && !opts->full_auxtrace) {
139		pr_err("Snapshot mode (-S option) requires " INTEL_BTS_PMU_NAME " PMU event (-e " INTEL_BTS_PMU_NAME ")\n");
140		return -EINVAL;
141	}
142
143	if (!opts->full_auxtrace)
144		return 0;
145
146	if (opts->full_auxtrace && !perf_cpu_map__empty(cpus)) {
147		pr_err(INTEL_BTS_PMU_NAME " does not support per-cpu recording\n");
148		return -EINVAL;
149	}
150
151	/* Set default sizes for snapshot mode */
152	if (opts->auxtrace_snapshot_mode) {
153		if (!opts->auxtrace_snapshot_size && !opts->auxtrace_mmap_pages) {
154			if (privileged) {
155				opts->auxtrace_mmap_pages = MiB(4) / page_size;
156			} else {
157				opts->auxtrace_mmap_pages = KiB(128) / page_size;
158				if (opts->mmap_pages == UINT_MAX)
159					opts->mmap_pages = KiB(256) / page_size;
160			}
161		} else if (!opts->auxtrace_mmap_pages && !privileged &&
162			   opts->mmap_pages == UINT_MAX) {
163			opts->mmap_pages = KiB(256) / page_size;
164		}
165		if (!opts->auxtrace_snapshot_size)
166			opts->auxtrace_snapshot_size =
167				opts->auxtrace_mmap_pages * (size_t)page_size;
168		if (!opts->auxtrace_mmap_pages) {
169			size_t sz = opts->auxtrace_snapshot_size;
170
171			sz = round_up(sz, page_size) / page_size;
172			opts->auxtrace_mmap_pages = roundup_pow_of_two(sz);
173		}
174		if (opts->auxtrace_snapshot_size >
175				opts->auxtrace_mmap_pages * (size_t)page_size) {
176			pr_err("Snapshot size %zu must not be greater than AUX area tracing mmap size %zu\n",
177			       opts->auxtrace_snapshot_size,
178			       opts->auxtrace_mmap_pages * (size_t)page_size);
179			return -EINVAL;
180		}
181		if (!opts->auxtrace_snapshot_size || !opts->auxtrace_mmap_pages) {
182			pr_err("Failed to calculate default snapshot size and/or AUX area tracing mmap pages\n");
183			return -EINVAL;
184		}
185		pr_debug2("Intel BTS snapshot size: %zu\n",
186			  opts->auxtrace_snapshot_size);
187	}
188
189	/* Set default sizes for full trace mode */
190	if (opts->full_auxtrace && !opts->auxtrace_mmap_pages) {
191		if (privileged) {
192			opts->auxtrace_mmap_pages = MiB(4) / page_size;
193		} else {
194			opts->auxtrace_mmap_pages = KiB(128) / page_size;
195			if (opts->mmap_pages == UINT_MAX)
196				opts->mmap_pages = KiB(256) / page_size;
197		}
198	}
199
200	/* Validate auxtrace_mmap_pages */
201	if (opts->auxtrace_mmap_pages) {
202		size_t sz = opts->auxtrace_mmap_pages * (size_t)page_size;
203		size_t min_sz;
204
205		if (opts->auxtrace_snapshot_mode)
206			min_sz = KiB(4);
207		else
208			min_sz = KiB(8);
209
210		if (sz < min_sz || !is_power_of_2(sz)) {
211			pr_err("Invalid mmap size for Intel BTS: must be at least %zuKiB and a power of 2\n",
212			       min_sz / 1024);
213			return -EINVAL;
214		}
215	}
216
217	if (intel_bts_evsel) {
218		/*
219		 * To obtain the auxtrace buffer file descriptor, the auxtrace event
220		 * must come first.
221		 */
222		evlist__to_front(evlist, intel_bts_evsel);
223		/*
224		 * In the case of per-cpu mmaps, we need the CPU on the
225		 * AUX event.
226		 */
227		if (!perf_cpu_map__empty(cpus))
228			evsel__set_sample_bit(intel_bts_evsel, CPU);
229	}
230
231	/* Add dummy event to keep tracking */
232	if (opts->full_auxtrace) {
233		struct evsel *tracking_evsel;
234		int err;
235
236		err = parse_event(evlist, "dummy:u");
237		if (err)
238			return err;
239
240		tracking_evsel = evlist__last(evlist);
241
242		evlist__set_tracking_event(evlist, tracking_evsel);
243
244		tracking_evsel->core.attr.freq = 0;
245		tracking_evsel->core.attr.sample_period = 1;
246	}
247
248	return 0;
249}
250
251static int intel_bts_parse_snapshot_options(struct auxtrace_record *itr,
252					    struct record_opts *opts,
253					    const char *str)
254{
255	struct intel_bts_recording *btsr =
256			container_of(itr, struct intel_bts_recording, itr);
257	unsigned long long snapshot_size = 0;
258	char *endptr;
259
260	if (str) {
261		snapshot_size = strtoull(str, &endptr, 0);
262		if (*endptr || snapshot_size > SIZE_MAX)
263			return -1;
264	}
265
266	opts->auxtrace_snapshot_mode = true;
267	opts->auxtrace_snapshot_size = snapshot_size;
268
269	btsr->snapshot_size = snapshot_size;
270
271	return 0;
272}
273
274static u64 intel_bts_reference(struct auxtrace_record *itr __maybe_unused)
275{
276	return rdtsc();
277}
278
279static int intel_bts_alloc_snapshot_refs(struct intel_bts_recording *btsr,
280					 int idx)
281{
282	const size_t sz = sizeof(struct intel_bts_snapshot_ref);
283	int cnt = btsr->snapshot_ref_cnt, new_cnt = cnt * 2;
284	struct intel_bts_snapshot_ref *refs;
285
286	if (!new_cnt)
287		new_cnt = 16;
288
289	while (new_cnt <= idx)
290		new_cnt *= 2;
291
292	refs = calloc(new_cnt, sz);
293	if (!refs)
294		return -ENOMEM;
295
296	memcpy(refs, btsr->snapshot_refs, cnt * sz);
297
298	btsr->snapshot_refs = refs;
299	btsr->snapshot_ref_cnt = new_cnt;
300
301	return 0;
302}
303
304static void intel_bts_free_snapshot_refs(struct intel_bts_recording *btsr)
305{
306	int i;
307
308	for (i = 0; i < btsr->snapshot_ref_cnt; i++)
309		zfree(&btsr->snapshot_refs[i].ref_buf);
310	zfree(&btsr->snapshot_refs);
311}
312
313static void intel_bts_recording_free(struct auxtrace_record *itr)
314{
315	struct intel_bts_recording *btsr =
316			container_of(itr, struct intel_bts_recording, itr);
317
318	intel_bts_free_snapshot_refs(btsr);
319	free(btsr);
320}
321
322static int intel_bts_snapshot_start(struct auxtrace_record *itr)
323{
324	struct intel_bts_recording *btsr =
325			container_of(itr, struct intel_bts_recording, itr);
326	struct evsel *evsel;
327
328	evlist__for_each_entry(btsr->evlist, evsel) {
329		if (evsel->core.attr.type == btsr->intel_bts_pmu->type)
330			return evsel__disable(evsel);
331	}
332	return -EINVAL;
333}
334
335static int intel_bts_snapshot_finish(struct auxtrace_record *itr)
336{
337	struct intel_bts_recording *btsr =
338			container_of(itr, struct intel_bts_recording, itr);
339	struct evsel *evsel;
340
341	evlist__for_each_entry(btsr->evlist, evsel) {
342		if (evsel->core.attr.type == btsr->intel_bts_pmu->type)
343			return evsel__enable(evsel);
344	}
345	return -EINVAL;
346}
347
348static bool intel_bts_first_wrap(u64 *data, size_t buf_size)
349{
350	int i, a, b;
351
352	b = buf_size >> 3;
353	a = b - 512;
354	if (a < 0)
355		a = 0;
356
357	for (i = a; i < b; i++) {
358		if (data[i])
359			return true;
360	}
361
362	return false;
363}
364
365static int intel_bts_find_snapshot(struct auxtrace_record *itr, int idx,
366				   struct auxtrace_mmap *mm, unsigned char *data,
367				   u64 *head, u64 *old)
368{
369	struct intel_bts_recording *btsr =
370			container_of(itr, struct intel_bts_recording, itr);
371	bool wrapped;
372	int err;
373
374	pr_debug3("%s: mmap index %d old head %zu new head %zu\n",
375		  __func__, idx, (size_t)*old, (size_t)*head);
376
377	if (idx >= btsr->snapshot_ref_cnt) {
378		err = intel_bts_alloc_snapshot_refs(btsr, idx);
379		if (err)
380			goto out_err;
381	}
382
383	wrapped = btsr->snapshot_refs[idx].wrapped;
384	if (!wrapped && intel_bts_first_wrap((u64 *)data, mm->len)) {
385		btsr->snapshot_refs[idx].wrapped = true;
386		wrapped = true;
387	}
388
389	/*
390	 * In full trace mode 'head' continually increases.  However in snapshot
391	 * mode 'head' is an offset within the buffer.  Here 'old' and 'head'
392	 * are adjusted to match the full trace case which expects that 'old' is
393	 * always less than 'head'.
394	 */
395	if (wrapped) {
396		*old = *head;
397		*head += mm->len;
398	} else {
399		if (mm->mask)
400			*old &= mm->mask;
401		else
402			*old %= mm->len;
403		if (*old > *head)
404			*head += mm->len;
405	}
406
407	pr_debug3("%s: wrap-around %sdetected, adjusted old head %zu adjusted new head %zu\n",
408		  __func__, wrapped ? "" : "not ", (size_t)*old, (size_t)*head);
409
410	return 0;
411
412out_err:
413	pr_err("%s: failed, error %d\n", __func__, err);
414	return err;
415}
416
417struct auxtrace_record *intel_bts_recording_init(int *err)
418{
419	struct perf_pmu *intel_bts_pmu = perf_pmus__find(INTEL_BTS_PMU_NAME);
420	struct intel_bts_recording *btsr;
421
422	if (!intel_bts_pmu)
423		return NULL;
424
425	if (setenv("JITDUMP_USE_ARCH_TIMESTAMP", "1", 1)) {
426		*err = -errno;
427		return NULL;
428	}
429
430	btsr = zalloc(sizeof(struct intel_bts_recording));
431	if (!btsr) {
432		*err = -ENOMEM;
433		return NULL;
434	}
435
436	btsr->intel_bts_pmu = intel_bts_pmu;
437	btsr->itr.pmu = intel_bts_pmu;
438	btsr->itr.recording_options = intel_bts_recording_options;
439	btsr->itr.info_priv_size = intel_bts_info_priv_size;
440	btsr->itr.info_fill = intel_bts_info_fill;
441	btsr->itr.free = intel_bts_recording_free;
442	btsr->itr.snapshot_start = intel_bts_snapshot_start;
443	btsr->itr.snapshot_finish = intel_bts_snapshot_finish;
444	btsr->itr.find_snapshot = intel_bts_find_snapshot;
445	btsr->itr.parse_snapshot_options = intel_bts_parse_snapshot_options;
446	btsr->itr.reference = intel_bts_reference;
447	btsr->itr.read_finish = auxtrace_record__read_finish;
448	btsr->itr.alignment = sizeof(struct branch);
449	return &btsr->itr;
450}
451